Tire condition advisory system

ABSTRACT

A pressure detection device and a controller in communication with the device are used to implement a tire pressure optimization system for a vehicle. The pressure detection device detects a vehicle tire&#39;s inflation pressure. The controller is programmed to identify the vehicle as being in a warning state when the inflation pressure is below a warning low pressure threshold, identify the vehicle as being in an optimum state when the inflation pressure is within an optimum pressure range where the vehicle will exhibit optimum performance, and identify the vehicle as being in an advisory state when the inflation pressure is within an advisory pressure range where the vehicle will exhibit an undesirable performance characteristic. The advisory pressure range is outside of the optimum pressure range and above the warning low pressure threshold.

TECHNICAL FIELD

The embodiments disclosed herein generally relate to the monitoring oftire conditions in vehicles.

BACKGROUND

The United States National Highway Traffic Safety Administration (NHTSA)requires vehicle manufacturers to equip vehicles with a tire pressuremonitoring system (TPMS) to detect when one or more of a vehicle's tiresare significantly under inflated. Recommended tire inflation pressuresare defined by the vehicle manufacturers and provided to drivers in theform of placards, usually located on the driver's side door. At present,the NHTSA requires the driver of a vehicle to be alerted with a telltaleif the tire inflation pressure in one or more of the tires is below thehigher of a pressure 25% below the vehicle manufacturer's placardpressure or a specified minimum pressure for the specific type of tireon the vehicle. The required telltale is commonly implemented in theform of a malfunction indicator light in the vehicle's instrument panel.

SUMMARY

Disclosed herein are embodiments for implementing a tire conditionadvisory system in a vehicle.

In one aspect, a tire pressure optimization system for a vehiclecomprises: a pressure detection device for detecting a vehicle tire'sinflation pressure; and a controller in communication with the device,the controller programmed to: identify the vehicle as being in a warningstate when the inflation pressure is below a warning low pressurethreshold, identify the vehicle as being in an optimum state when theinflation pressure is within an optimum pressure range where the vehiclewill exhibit optimum performance, and identify the vehicle as being inan advisory state when the inflation pressure is within an advisorypressure range where the vehicle will exhibit an undesirable performancecharacteristic, wherein the advisory pressure range is outside of theoptimum pressure range and above the warning low pressure threshold.

In another aspect, a vehicle comprises: a tire; a device for detectingthe tire's inflation pressure; and a controller in communication withthe device, the controller programmed to: identify the vehicle as beingin a warning state when the inflation pressure is below a warning lowpressure threshold, identify the vehicle as being in an optimum statewhen the inflation pressure is within an optimum pressure range wherethe vehicle will exhibit optimum performance, and identify the vehicleas being in an advisory state when the inflation pressure is within anadvisory pressure range where the vehicle will exhibit an undesirableperformance characteristic, wherein the advisory pressure range isoutside of the optimum pressure range and above the warning low pressurethreshold.

In another aspect, a vehicle comprises: a plurality of tires; aplurality of devices, each associated with one of the plurality of tiresfor detecting the associated tires' inflation pressures; and acontroller in communication with the plurality of devices, thecontroller programmed to: calculate a pressure differential between afirst inflation pressure of one of the plurality of tires and a secondinflation pressure of another of the plurality of tires, identify thevehicle as being in a warning state when any of the inflation pressuresare below a warning low pressure threshold or above a warning highpressure threshold, identify the vehicle as being in an optimum statewhen all of the inflation pressures are within an optimum pressure rangewhere the vehicle will exhibit optimum performance, the optimum pressurerange defined for each inflation pressure by an optimum low pressurethreshold, an optimum high pressure threshold, and an optimum pressuredifferential from another vehicle tire's inflation pressure, andidentify the vehicle as being in an advisory state when any of theinflation pressures are within an advisory pressure range where thevehicle will exhibit an undesirable performance characteristic, theadvisory pressure range for each inflation pressure defined as includingany inflation pressure that is between the optimum low pressurethreshold and the warning low pressure threshold, between the optimumhigh pressure threshold and the warning high pressure threshold, oroutside of the optimum pressure differential from another vehicle tire'sinflation pressure.

These and other aspects will be described in additional detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features, advantages and other uses of the present systemand method will become more apparent by referring to the followingdetailed description and drawings in which:

FIG. 1 is a perspective view of the passenger compartment of a vehicle;

FIG. 2 is a partially cut away perspective view of one of the tires ofthe vehicle, showing an example of a device for detecting the tire'sinflation pressure;

FIG. 3 is a block diagram showing a control system for reading thetire's inflation pressure and operating displays and audio outputdevices of the vehicle;

FIG. 4 is a flow diagram depicting operations of a tire inflationpressure advisory system for identifying whether the vehicle is in awarning state, an advisory state or an optimum state based on theinflation pressures detected for the tires, and for outputtingindications relating to the identified state;

FIG. 5 is a representation of an example tire inflation pressure map foridentifying whether the vehicle is in the warning state, the advisorystate or the optimum state with respect to a particular tire accordingto the flow diagram of FIG. 4;

FIG. 6 is a flow diagram depicting operations for outputting a warningstate indication when the vehicle is identified as being in the warningstate;

FIG. 7 is a flow diagram depicting operations for outputting an advisorystate indication when the vehicle is identified as being in the advisorystate;

FIG. 8 is a flow diagram depicting operations for outputting an optimumstate indication when the vehicle is identified as being in the optimumstate; and

FIGS. 9-12 show example display configurations for the displays duringimplementation of the tire inflation pressure advisory system accordingto the flow diagrams of FIGS. 6-8.

DETAILED DESCRIPTION

Existing TPMS logic is responsive to a determination that one or more ofa vehicle's tires are significantly under inflated. This disclosuredescribes examples of systems and methods for advising the operator of avehicle, under conditions that would not call for the operator to bealerted under existing TPMS logic, that the vehicle is exhibitingundesirable performance characteristics because the inflation pressuresin one or more of the vehicle's tires are outside of an optimum pressurerange.

FIG. 1 depicts a partial view of the front passenger compartment 12 of avehicle 10. A dash 14 extends transversely across the vehicle 10 andserves as a forward boundary for the front passenger compartment 12. Asshown, the dash 14 includes an instrument panel 16, and a center stack18 extends downward from the dash 14.

The front passenger compartment 12 includes a number of features forpresenting information to an operator or other user of the vehicle 10.For instance, as shown in FIG. 1, the instrument panel 16 includes amongother components an electronic display 20, gauges 22 and a malfunctionindicator light 24. In addition, an information/entertainment system 30with another electronic display 32 is located in the center stack 18.Further, the front passenger compartment 12 can include one or moreaudio devices 34 for audibly presenting information to an operator orother user of the vehicle 10.

The gauges 22 are configured to indicate vehicle operating conditionsincluding, for example, the rotation speed of an engine or motorpowering the vehicle 10 and the speed at which the vehicle 10 istraveling. The illustrated malfunction indicator light 24 is a back litindicator positioned on a gauge 22, but could be otherwise located inthe field of view of an operator of the vehicle 10. The malfunctionindicator light 24 could additionally or alternatively be implemented,for example, as a facsimile of a back lit indicator. For instance, inthe illustrated vehicle 10, the malfunction indicator light 24 could beimplemented in the display 20, the display 32 or another display.

As discussed with additional reference to FIG. 2, the malfunctionindicator light 24 can be illuminated or otherwise actuated in order toprovide a warning to the operator of the vehicle 10 that concerns theinflation pressure in one or more of the vehicle's 10 pneumatic tires40.

In this example, the malfunction indicator light 24 can operate inconjunction with a TPMS for the vehicle 10. In accordance with presentregulations in the United States under the NHTSA, the vehicle 10 caninclude a TPMS configured to actuate the malfunction indicator light 24or a similar telltale to provide a warning of low tire inflationpressure if the inflation pressure in any of the tires 40 is below thehigher of a pressure 25% below a placard inflation pressure for the tire40 (i.e., a recommended inflation pressure as defined by themanufacturer of the vehicle 10 and provided to the operator in the formof a placard, usually located on the driver's side door of the vehicle10) or a minimum pressure specified for the tire 40 by the NHTSA.Although this TPMS logic is provided as one non-limiting example, itwill be understood that a TPMS could be configured in accordance withother regulations in the United States, for example, or in accordancewith the TPMS or similar regulations enacted by regulatory entities indifferent countries.

As shown with additional reference to FIG. 3, to implement a TPMS, thevehicle 10 can incorporate one or more tire pressure detection devices42 for sensing or otherwise detecting the inflation pressures of one ormore of a front left (FL) tire 40, a front right (FR) tire 40, a rearleft (RL) tire 40 and a rear right (RR) tire 40. According to a commonconfiguration of a so-called direct TPMS, for example, the vehicle 10may be equipped with a pressure sensor 44 in each tire 40 for sensingthe inflation pressures of each of the tires 40. Each pressure sensor 44can be mounted on the wheel 46 of a respective tire 40, for example witha valve stem 48 as shown in FIG. 2, or otherwise in the tire 40.Alternatively, the vehicle 10 may be configured to employ a so-calledindirect TPMS. In a common configuration of indirect TPMS, the inflationpressures of one, some or all of the tires 40 are inferred using inputfrom wheel speed sensors 50 included in the ABS hardware for the vehicle10, as indicated in FIG. 3.

The forgoing configurations of TPMS are described as non-limitingexamples. In other implementations of TPMS, any manner of pressuresensors 44, wheel speed sensors 50 or other sensors 52, either alone orin any combination with each other or with other componentry, can beused in sensing or otherwise detecting the inflation pressures of one ormore of the tires 40 of the vehicle 10. Below, the non-limiting examplesof pressure sensors 44, wheel speed sensors 50, other sensors 52 andother applicable componentry are encompassed by the representative tirepressure detection devices 42.

As shown in FIG. 3, the display 20, the display 32, the audio device 34and optionally the malfunction indicator light 24 are adaptable underthe control of a controller 60. The controller 60 can control the outputof the display 20, the display 32, the audio device 34 and optionallythe malfunction indicator light 24 to implement a tire inflationpressure advisory system 70. As explained in additional detail below,the tire inflation pressure advisory system 70 can be used to identifyan operating state of the vehicle 10 relating to the inflation pressurein one or more of the tires 40 and output indications relating to theidentified operating state.

The logic for controlling the tire inflation pressure advisory system 70is embodied in the controller 60. The controller 60 could be one ormultiple microcomputers including a random access memory (RAM), aread-only memory (ROM) and a central processing unit (CPU) in additionto various input and output connections. Generally, the controlfunctions described herein can be implemented by one or more softwareprograms stored in internal or external memory and are performed byexecution by the CPU. However, some or all of the functions could alsobe implemented by hardware components.

The controller 60 can be directly or indirectly communicatively coupledwith the tire pressure detection devices 42 as generally shown. Thecontroller 60 continually receives input signals originating from thetire pressure detection devices 42 indicative of the real-time inflationpressures for each of the tires 40 of the vehicle 10. For each of theinput signals received from the tire pressure detection devices 42, thecontroller 60 may also receive an indication of which tire 40 of thevehicle 10 the input signal is associated with. This indication can beimplicit in the input signals themselves, for example, or otherwisecommunicated to the controller 60. Alternatively, the tire 40 associatedwith the input signal can be identified using position detectionthrough, for example, triangulation calculation using a detected signalstrength of the tire pressure detection device 42.

The controller 60 monitors and evaluates the input signals from the tirepressure detection devices 42. In the illustrated example, thecontroller 60 can actuate the malfunction indicator light 24 in order toimplement a TPMS for the vehicle 10 as a part of the overall tireinflation pressure advisory system 70. In this example, if themalfunction indicator light 24 is the illustrated back lit indicator,the controller 60 can actuate the malfunction indicator light 24 bycausing it to be illuminated. However, it will be understood that thecontroller 60 can actuate additional or alternative malfunctionindicator lights 24 implemented, for example, in the display 20, thedisplay 32 or another display.

Irrespective of whether the TPMS for the vehicle 10 is implemented bythe controller 60 as a part of the overall tire inflation pressureadvisory system 70, it is contemplated that the tire pressure detectiondevices 42 can be those associated with the TPMS. In this manner,existing equipment of the vehicle 60 can be used to implement the tireinflation pressure advisory system 70. In alternative examples, however,the vehicle 10 could be equipped with additional non-TPMS-related tirepressure detection devices 42 for sensing or otherwise detecting theinflation pressures of one or more of the tires 40.

As shown, the controller 60 is further communicatively coupled with oneor more of the display 20, the display 32 and the audio device 34. Thedisplays 20 and 32 are representative and non-limiting examples ofdevices adaptable under the control of the controller 60 to outputinformation to an operator of the vehicle 10 in a visible format.Although each of the displays 20 and 32 are shown as a singulardisplays, the display 20 and/or the display 32 could be embodied inmultiple discrete displays, for example. The display functions describedherein could be performed using either one of the displays 20 and 32individually, or using both of the displays 20 and 32 in combination. Inalternative examples, some or all of the display functions could beperformed using a so-called heads up display, for instance.

The audio device 34 is similarly a representative and non-limitingexample of a device adaptable under the control of the controller 60 tooutput information to an operator of the vehicle 10 in an audibleformat. The audio device 34 could be one or more speakers, for example,associated with the information/entertainment system 30. The audiblefunctions described herein could be performed individually or incombination with the display functions described with reference to thedisplays 20 and 32.

In operation of the tire inflation pressure advisory system 70, for eachof the tires 40 of the vehicle 10, the controller 60 identifies thevehicle 10 as being in one of a warning state, an advisory state or anoptimum state with respect to the tire 40 based on the detectedinflation pressure for the tire 40. In addition, the controller 60 cancontrol the display 20, the display 32, the audio device 34 and/or themalfunction indicator light 24 to selectively provide to an operator ofthe vehicle 10 information pertaining to the inflation pressures of thetire 40 and indications concerning the identified state of the vehicle10, along with other information.

An exemplary process 100 for implementing the tire inflation pressureadvisory system 70 is shown in FIG. 4. Although the process 100 isexplained for simplicity with respect to a single one of the tires 40 ofthe vehicle 10, it will be understood that the operations of the process100 are applicable to each of the tires 40. The following examplesassume that a placard inflation pressure P for the tire 40 is 35 poundsper square inch (psi). However, this is given as a representative andnon-limiting example that could vary depending upon the particularvehicle 10 and/or tire 40. The examples as needed also assume previousor concurrent detection of the inflation pressures of one or more of theother tires 40 of the vehicle 10.

The process 100 is explained with reference to FIG. 5, which illustratesa tire inflation pressure map with non-limiting examples of a warning,advisory and an optimum pressure ranges for the inflation pressures ofthe tire 40. The warning pressure range, the advisory pressure range andthe optimum pressure range respectively correspond to the warning state,the advisory state and the optimum state of the vehicle 10. That is, ifthe controller 60 recognizes that the inflation pressure of the tire 40is in the warning pressure range, the controller 60 will identify thevehicle 10 as being in the warning state with respect to the tire 40, ifthe controller 60 recognizes that the inflation pressure of the tire 40is in the advisory pressure range, the controller 60 will identify thevehicle 10 as being in the advisory state with respect to the tire 40,and if the controller 60 recognizes that the inflation pressure of thetire 40 is in the optimum pressure range, the controller 60 willidentify the vehicle 10 as being in the optimum state with respect tothe tire 40.

The warning pressure range, the advisory pressure range and the optimumpressure range can each be defined based on regulatory and/orperformance criteria for the vehicle 10. According to the tire inflationpressure map of FIG. 5 and the examples that follow, these criteria canbe constructed to consider the detected inflation pressure for the tire40 either alone or in combination with the detected inflation pressuresof one or more other tires 40 of the vehicle 10. In FIG. 5, inflationpressures for the tire 40 are mapped on the vertical axis, whiledifferentials between an inflation pressure of the tire 40 and theinflation pressure of another tire 40 on the vehicle 10 are mapped onthe horizontal axis. One example of such a differential pressureincludes the differential between an inflation pressure of a tire 40 onone side of the vehicle 10 and an inflation pressure of another tire 40on the opposing side of the vehicle 10. Another example of such adifferential includes the differential between an inflation pressure ofa tire 40 on a forward end of the vehicle 10 and an inflation pressureof a tire 40 on the rearward end of the vehicle 10.

It can be seen from the tire inflation pressure map in FIG. 5 and theexamples that follow that the warning pressure range, the advisorypressure range and the optimum pressure range may include, but are notlimited to including, only one set of continuous inflation pressures orother values. Instead, in some examples, multiple sets of inflationpressures or other values can be included depending, for instance, onthe amount of criteria constructed to define the respective warningpressure range, the advisory pressure range and the optimum pressurerange. According to the non-limiting examples herein, the sets ofinflation pressures or other values can generally be closed or openended continuous sets. However, it will be understood that in otherexamples the sets of inflation pressures or other values couldalternatively be non-continuous, for instance.

In addition, it can be seen that the advisory pressure range in thenon-limiting examples can be multidimensional if, for instance, multiplecriteria with differing units are constructed to define the advisorypressure range. It can similarly be seen that the optimum pressure rangein the non-limiting examples can be multidimensional if multiplecriteria with differing units are constructed to define the optimumpressure range. Although the warning pressure range in the non-limitingexamples is generally defined in a single dimension, it will beunderstood that in other examples the warning pressure range couldalternatively be multidimensional.

In general, the warning pressure range is defined to include at leastany inflation pressures of the tire 40 that are below a warning lowpressure threshold WLPT set according to the above described or otherTPMS logic. That is, the warning pressure range is defined to includeany inflation pressures of the tire 40 that require a warning of lowtire inflation pressure under TPMS regulations. For instance, accordingto existing TPMS regulations in the United States under the NHTSA, forthe given example of the tire 40 with a placard inflation pressure P of35 psi, the warning low pressure threshold WLPT would be the higher of26.25 psi (i.e., 25% below the placard inflation pressure P) or theminimum pressure specified for the tire 40 by the NHTSA. As shown, thewarning pressure range can optionally be defined to additionally includeany inflation pressures of the tire 40 that are above a warning highpressure threshold WHPT. The warning high pressure threshold WHPT mayfor example represent an upper limit for the inflation pressure of thetire 40. For the given example of the tire 40 with a placard inflationpressure P of 35 psi, for instance, the warning high pressure thresholdWHPT could be approximately 63.5 psi. The warning high pressurethreshold WHPT could alternatively represent an upper limit to thedetection capability of the pressure sensor 44, such that an errorcondition is indicated if the inflation pressure of the tire 40 is abovethe detection capability of the pressure sensor 44.

The optimum pressure range includes inflation pressures of the tire 40that fall outside of the warning pressure range, and that will not causethe vehicle 10 to exhibit undesirable performance characteristics. Thatis, if the inflation pressures of the tires 40 are in the optimum range,the vehicle 10 will exhibit optimum performance characteristics.

The advisory pressure range is shown and explained with correspondingreference to the optimum pressure range. The advisory pressure range,like the optimum pressure range, includes inflation pressures of thetire 40 that fall outside of the warning pressure range. However, unlikethe optimum pressure range, the advisory pressure range includesinflation pressures of the tire 40 that will, either alone or incombination with the inflation pressures of one or more other tires 40of the vehicle 10, cause the vehicle 10 to exhibit one or moreundesirable performance characteristics. These undesirable performancecharacteristics may include, for example, undesirable ridecharacteristics, such as shake, a harsh ride, drift/pull or shimmy; anundesirable efficiency characteristic, such as poor fuel economyperformance; or an undesirable tire wear characteristic, such as poortire wear performance.

The demarcation between the optimum pressure range and the advisorypressure range can generally be determined based on the sensitivity ofthe vehicle 10 to exhibit one or more of the above described or otherundesirable performance characteristics when the inflation pressure ofthe tire 40 varies from the placard inflation pressure P and/or from theinflation pressure of another tire 40 of the vehicle 10.

In the example of FIG. 5, the advisory pressure range is defined toinclude any inflation pressures of the tire 40 that are above thewarning low pressure threshold WLPT but below an optimum low pressurethreshold OLPT. The optimum low pressure threshold OLPT can be set belowthe placard inflation pressure P considering, for example, that thevehicle 10 will exhibit poor fuel economy performance and/or poor tirewear performance if the inflation pressure of the tire 40 is below theoptimum low pressure threshold OLPT.

The example advisory pressure range is also defined to include anyinflation pressures of the tire 40 that are below the warning highpressure threshold WHPT but above an optimum high pressure thresholdOHPT. The optimum high pressure threshold OHPT can be set above theplacard inflation pressure P considering, for example, that the vehicle10 will exhibit poor fuel economy performance, shake, and/or a harshride if the inflation pressure of the tire 40 is above the optimum highpressure threshold OHPT.

The example advisory pressure range is further defined to include anyinflation pressures of the tire 40 that are outside of an optimumpressure differential OΔP from the inflation pressure of another tire 40on the vehicle 10, such as a tire 40 on an opposing side of the vehicle10. The optimum pressure differential OΔP can be set considering, forexample, that the vehicle 10 will exhibit drift or pull if the inflationpressure of the tire 40 is outside of the optimum pressure differentialOΔP from the inflation pressure of another tire 40 on the vehicle 10(e.g, if the inflation pressure of the FL tire 40 is outside of theoptimum pressure differential OΔP from the inflation pressure of the FRtire 40, or if the inflation pressure of the RL tire 40 is outside ofthe optimum pressure differential OΔP from the inflation pressure of theRR tire 40). The optimum pressure differential OΔP can further be setconsidering, for example, that the vehicle 10 will exhibit shimmy, oroscillation, if the if the differential between the inflation pressuresof two opposing steering tires 40 (e.g., the FL tire 40 and the FR tire40) is outside of the optimum pressure differential OΔP.

The values of the optimum low pressure threshold OLPT, the optimum highpressure threshold OHPT and the optimum pressure differential OΔP can bedetermined based on a predetermined and/or heuristic evaluation of thesensitivity of the vehicle 10 to exhibit particular undesirableperformance characteristics based on the inflation pressures of one ormore of the tires 40. For the given example of the tire 40, forinstance, the optimum low pressure threshold OLPT could be approximately5 psi below the placard inflation pressure P of 35 psi, or 30 psi, theoptimum high pressure threshold OHPT could be approximately 5 psi abovethe placard inflation pressure P of 35 psi, or 40 psi, and the optimumpressure differential OΔP could be approximately ±3 psi from theinflation pressure of the tire 40 to the inflation pressure of anothertire 40 on the vehicle 10.

It will be understood that the illustrated and described advisorypressure range is a non-limiting example. In other examples, theadvisory pressure range can be defined with different values for theoptimum low pressure threshold OLPT, the optimum high pressure thresholdOHPT, the optimum pressure differential OΔP, the warning low pressurethreshold WLPT, and/or the warning high pressure threshold WHPT. Inother examples, the advisory pressure range can be defined withoutreference to one or more of the optimum low pressure threshold OLPT, theoptimum high pressure threshold OHPT and the optimum pressuredifferential OΔP. In yet other examples, the advisory pressure range canbe defined with reference to other thresholds or differentials set inconsideration of additional and/or alternative undesirable performancecharacteristics from those specifically described.

In operation S102 of the process 100, it is determined whether theinflation pressure of the tire 40 is beyond a warning pressurethreshold. If the inflation pressure of the tire 40 is determined to bebelow the warning low pressure threshold WLPT (or optionally above thewarning high pressure threshold WHPT), the inflation pressure of thetire 40 is recognized as being in the warning pressure range, and inoperation S104, the vehicle 10 is identified as being in the warningstate.

As shown in FIG. 5, an example inflation pressure A of the tire 40 is inthe warning pressure range for being below the warning low pressurethreshold WLPT, and an example inflation pressure B is in the warningpressure range for being above the warning high pressure threshold WHPT.In the example process 100, it can be seen that the although theinflation pressures A and B of the tire 40 may additionally becharacteristic of the advisory pressure range in one or more ways (e.g.,the inflation pressures A and B may be below the optimum low pressurethreshold OLPT, above the optimum high pressure threshold OHPT, and/oroutside of the optimum pressure differential OΔP from the inflationpressure of another tire 40 on the vehicle 10, as explained below), thevehicle 10 will only be identified as being in the warning state, andnot the advisory state, if any of the conditions of operation S102 issatisfied. If the vehicle 10 is identified as being in the warning statein operation S104, the malfunction indicator light 24 and optionally thedisplay 20, the display 32 and/or the audio device 34 are controlled tooutput a warning state indication in operation S106, as explained inadditional detail below.

If the inflation pressure of the tire 40 is recognized as being outsideof the warning pressure range, in operation S110, it is determinedwhether the inflation pressure of the tire 40 is nonetheless outside ofthe optimum pressure range where the vehicle 10 will exhibit optimumperformance. That is, it is determined in operation S110 whether theinflation pressure of the tire 40 is within the advisory pressure rangewhere the inflation pressure of the tire 40 will, either alone or incombination with the inflation pressures of one or more other tires 40of the vehicle 10, cause the vehicle 10 to exhibit one or moreundesirable performance characteristics.

The inflation pressure of the tire 40 can be, for example, recognized asbeing in the advisory pressure range in operation S110 a if theinflation pressure of the tire 40 is below the optimum low pressurethreshold OLPT. As shown in FIG. 5, an example inflation pressure C ofthe tire 40 is in the advisory pressure range for being below theoptimum low pressure threshold OLPT. If the inflation pressure of thetire 40 is recognized as being in the advisory pressure range for beingbelow the optimum low pressure threshold OLPT in operation S110 a, itcan be inferred in operation S112 that the vehicle 10 is exhibiting poortire wear performance, and/or it can be inferred in operation S114 thatthe vehicle 10 is exhibiting poor fuel economy performance.

The inflation pressure of the tire 40 can also be recognized as being inthe advisory pressure range in operation S110 b if the inflationpressure of the tire 40 is above the optimum high pressure thresholdOHPT. As shown in FIG. 5, an example inflation pressure D of the tire 40is in the advisory pressure range for being above the optimum highpressure threshold OHPT. If the inflation pressure of the tire 40 isrecognized as being in the advisory pressure range for being above theoptimum high pressure threshold OHPT in operation S110 b, it can beinferred in operation S114 that the vehicle 10 is exhibiting poor fueleconomy performance, and/or it can be inferred in operation S116 thatthe vehicle 10 is exhibiting shake and/or a harsh ride.

The inflation pressure of the tire 40 can also be recognized as being inthe advisory pressure range in operation S110 c if the inflationpressure of the tire 40 is outside of the optimum pressure differentialOΔP from the inflation pressure of another tire 40 on the vehicle 10. Asshown in FIG. 5, an example inflation pressure E of the tire 40 is inthe advisory pressure range for being outside of the optimum pressuredifferential OΔP from the inflation pressure of an opposing tire 40. Inoperation S118, it can be inferred that the vehicle 10 is exhibitingdrift or pull if the inflation pressure of opposing side to side tires(e.g., FL tire 40 and FR tire 40, or RL tire 40 and RR tire 40) oropposing front to rear tires (e.g., FL tire 40 and RL tire 40, or FRtire 40 and RR tire 40) are outside of the optimum pressure differentialOΔP. In addition, it can be inferred in operation S120 that the vehicle10 is exhibiting shimmy if the differential between the inflationpressures of two opposing steering tires 40 (e.g., the FL tire 40 andthe FR tire 40) is outside of the optimum pressure differential OΔP.

If any of the conditions of operations S110 a-c is satisfied, inaddition to drawing inferences that the vehicle 10 is exhibiting one ormore undesirable performance characteristics in operations S112-S120,the inflation pressure of the tire 40 is recognized as being in theadvisory pressure range, and in operation S130, the vehicle 10 isidentified as being in the advisory state.

In the process 100, it can be seen that the although the exampleinflation pressures C, D and E of the tire 40 may be uncharacteristic ofthe advisory pressure range in one or more ways, the vehicle 10 willstill be identified as being in the advisory state if any of theconditions of operations S110 a-c is satisfied. For instance, as shownin FIG. 5, the inflation pressure C of the tire 40 is in the advisorypressure range for being below the optimum low pressure threshold OLPT,despite being within the optimum pressure differential OΔP from theinflation pressure of another tire 40 on the vehicle 10. Further, theinflation pressure D of the tire 40, although likewise within theoptimum pressure differential OΔP from the inflation pressure of anothertire 40 on the vehicle 10, is in the advisory pressure range for beingabove the optimum high pressure threshold OHPT. In addition, theinflation pressure E of the tire 40, despite being at the placardinflation pressure P, is in the advisory pressure range for beingoutside of the optimum pressure differential OΔP from the inflationpressure of an opposing tire 40.

It will also be understood that the conditions of operations S110 a-cmay be considered in parallel, for example, where the satisfaction ofone condition for recognizing the inflation pressure of the tire 40 asbeing in the advisory pressure range does not preclude the satisfactionof one or more other conditions for recognizing the inflation pressureof the tire 40 as being in the advisory pressure range. For instance, asshown in FIG. 5 and described by the flow of operations S110 a-c in FIG.4, an example inflation pressure F of the tire 40 could be recognized asbeing in the advisory range both for being above the optimum highpressure threshold OHPT and for being outside of the optimum pressuredifferential OΔP from the inflation pressure of another tire 40 on thevehicle 10. Similarly, an example inflation pressure G of the tire 40could be recognized as being in the advisory range both for being belowthe optimum low pressure threshold OLPT and for being outside of theoptimum pressure differential OΔP from the inflation pressure of anothertire 40 on the vehicle 10. In these and similar examples where aninflation pressure of the tire 40 is characteristic of the advisorypressure range in multiple ways, corresponding multiple inferences canbe drawn concerning undesirable performance characteristic that thevehicle 10 is exhibiting, as generally shown.

The above control in operations S110 a-c and/or operations S112-S120 canoptionally be combined with detection that the vehicle 10 is exhibitingone or more undesirable performance characteristics. Detection of theundesirable performance characteristics can be performed, for example,with other sensors 54 on the vehicle, such as accelerometers, steeringangle sensors, and yaw moment sensors. In this example, for instance, adetected undesirable performance characteristic could be used asconfirmation of an inference that the vehicle 10 is exhibiting theparticular undesirable performance characteristic. Alternatively, aparticular detected undesirable performance characteristic can becorrelated against the inflation pressures of the tires 40 to inferwhich tire inflation pressures of the tires 40, if any, are causing thevehicle 10 to exhibit the detected undesirable performancecharacteristic.

If the vehicle 10 is identified as being in the advisory state inoperation S130, the display 20, the display 32 and/or the audio device34 are controlled to output an advisory state indication in operationS132, as explained in additional detail below.

If none of the conditions of operations S102 and S110 for identifyingthe vehicle 10 as being in the warning state or the advisory state issatisfied, the inflation pressure of the tire 40 is recognized as beingin the optimum pressure range. As shown in FIG. 5, an example inflationpressure H of the tire 40 is in the optimum pressure range. Although theinflation pressure H of the tire 40 is below the placard inflationpressure P and varies from the inflation pressure of another tire 40 onthe vehicle 10 as shown, the inflation pressure H is in the optimumpressure range because none of the conditions of operations S102 andS110 for identifying the vehicle 10 as being in either the warning stateor the advisory state is satisfied. If the inflation pressure of thetire 40 is recognized as being in the optimum pressure range, inoperation S140 it can be inferred that the vehicle 10 is exhibitingoptimum performance with respect to the tire 40, and in operation S142,the vehicle 10 is identified as being in the optimum state. If thevehicle 10 is identified as being in the optimum state in operationS142, the display 20, the display 32 and/or the audio device 34 arecontrolled to output an optimum state indication in operation S144, asexplained in additional detail below.

Following the determination that the operating state of the vehicle 10is in one of the warning state, the advisory state or the optimum state,the tire inflation pressure advisory system 70 can provide appropriatefeedback or other information to an operator of the vehicle 10concerning the inflation pressures of the tires 40, including theactions required, if any, to ensure that the vehicle 10 is exhibitingoptimum performance with respect to the inflation pressures of the tires40.

For example, if the vehicle 10 is identified as being in the warningstate, in operation S106, the malfunction indicator light 24 andoptionally the display 20, the display 32 and/or the audio device 34 canbe controlled to output a warning state indication in operation 106 a.In addition to outputting the indication that the vehicle 10 is in thewarning state, as shown in FIG. 6, the warning state indication caninclude actuation of the malfunction indicator light 24 in accordancewith a TPMS when the inflation pressure is below the warning lowpressure threshold WLPT. Alternatively, the warning state indication caninclude an error state indication when the inflation pressure is abovethe warning high pressure threshold WHPT. Otherwise, the warning stateindication can include an indication associated with a low pressure whenthe inflation pressure is below the warning low pressure threshold WLPTor a high pressure when the inflation pressure is above the warning highpressure threshold WHPT. The warning state indication can furtheroptionally include, for example, outputting the inflation pressure ofthe tire 40 in operation S106 b and/or instructions for adjusting theinflation pressure of the tire 40 into the optimum pressure range inS106 c, so that the vehicle 10 will exhibit optimum performanceaccording to the optimum state.

Similarly, if the vehicle 10 is identified as being in the advisorystate, the display 20, the display 32 and/or the audio device 34 can becontrolled to output an advisory state indication in operation S132. Inaddition to outputting an indication that the vehicle 10 is in theadvisory state, as shown in FIG. 7, the advisory state indication caninclude, for example, outputting the inflation pressure of the tire 40in operation S132 a, a description of the one or more undesirableperformance characteristics that the vehicle is exhibiting because theinflation pressure of the tire 40 is outside of the optimum pressurerange and within the advisory pressure range in operation 132 b, and/orinstructions for adjusting the inflation pressure of the tire 40 intothe optimum pressure range in S132 c, so that the vehicle 10 willexhibit optimum performance according to the optimum state.

Further, as shown in FIG. 8, if the vehicle 10 is identified as being inthe optimum state, the display 20, the display 32 and/or the audiodevice 34 can be controlled to output an optimum state indicationaccording to operation S144. It will be understood that in one example,the optimum state indication can be output according to operation S144through the absence of a warning state indication according to operationS106 or an advisory state indication according to operation S132. Inaddition to outputting an indication that the vehicle 10 is in theoptimum state, the optimum state indication can include, for example,outputting the inflation pressure of the tire 40 in operation S144 aand/or a description of the one or more optimum performancecharacteristics that the vehicle is exhibiting because the inflationpressure of the tire 40 is within the optimum pressure range in S144 b.

Examples of configurations for the displays 20 and 32 in accordance withoperations S106, S132 and S144 are shown in FIGS. 9-12. Although onlyexample configurations for the displays 20 and 32 are depicted, it willbe understood that some or all of the information output at the displays20 and 32 can additionally or alternatively be output with the audiodevice 34.

According to the examples, the displays 20 and 32 can collectively orindividually be adapted to include one or both of a first field 200 aand a second field 200 b for outputting one or more aspects of thewarning state indication, the advisory state indication and the optimumstate indication described above. It will be understood that thedisplays 20 and 32 can be adapted to include either one of the firstfield 200 a and the second field 200 b, or both the first field 200 aand the second field 200 b. If the displays 20 and 32 are adapted toinclude both the first field 200 a and the second field 200 b, the firstfield 200 a and the second field 200 b could be selectively includedconcurrently, for example, or sequentially at the request of an operatorof the vehicle 10.

As shown throughout FIGS. 9-12, the first field 200 a may be dividedinto sectors 202 corresponding to the tires of the vehicle 10. Inparticular, according to an example of a common passenger vehicle, thefirst field 200 a contains four sectors 202 corresponding to arespective FL, a FR, a RL and a RR tire 40. As shown, each sector 202includes a background display 204 that can show different color hues,patterns or other indications to output whether the vehicle 10 is in thewarning state, the advisory state or the optimum state with respect to aparticular tire 40 of the vehicle 10.

In one non-limiting example, for instance, the background display 204can be controlled to show a red hue in accordance with operation S106 toindicate that the vehicle 10 is in the warning state with respect to aparticular tire 40, or to show a yellow hue in accordance with operationS132 to indicate that the vehicle 10 is in the advisory state withrespect to a particular tire 40. The background display 204 could becontrolled to show a standard background hue for the displays 20 and 32,for example, to indicate that the vehicle 10 is in the optimum statewith respect to a particular tire 40. In this manner, following thenon-limiting example above, the optimum state indication can be outputin accordance with operation S144 through the absence of showing a redhue to indicate that the vehicle 10 is in the warning state with respectto the particular tire 40 or showing a yellow hue to indicate that thevehicle 10 is in the advisory state with respect to the particular tire40. Alternatively, the background display 204 could be controlled toshow a green or other hue particular to the optimum state in accordancewith operation S144 to indicate that the vehicle 10 is in the optimumstate with respect to a particular tire 40.

In addition, each of the sectors 202 can show a numeric value 206 tooutput the inflation pressure of a corresponding tire 40 in theforeground of the background display 204, in accordance with operationsS106 b, S132 a and S144 a.

Moreover, as shown throughout FIGS. 10-12, if the vehicle 10 isidentified as being in either the warning state or the advisory statewith respect to a particular tire 40, each of the corresponding sectors202 can additionally show an appropriate symbol 208 in the foreground ofthe background display 204 to output an instruction according tooperations S106 c and S132 c for adjusting the inflation pressure of thetire 40 into the optimum pressure range so that the vehicle 10 willexhibit optimum performance characteristics. According to theillustrated examples, for instance, the symbol 208 may be an up arrow tooutput an instruction to adjust the inflation pressure of a tire 40upward into the optimum pressure range, and a down arrow to output aninstruction to adjust the inflation pressure of a tire 40 downward intothe optimum pressure range.

In another non-limiting example, the background display 204 for each ofthe corresponding sectors 202 could generally be controlled tocontinuously show a standard background hue for the displays 20 and 32.Each of the sectors 202 can show a numeric value 206 to output theinflation pressure of a corresponding tire 40 in the foreground of thebackground display 204, in accordance with operations S106 b, S132 a andS144 a, as described above. Furthermore, in this example, the hue of thenumeric value 206 shown may be changed in accordance with the respectiveoperations S106, S132 and S144 to indicate whether the vehicle 10 is inthe warning state, the advisory state or the optimum state with respectto a particular tire 40. For instance, the hue of the numeric value 206shown may be red in accordance with operation S106 to indicate that thevehicle 10 is in the warning state with respect to a particular tire 40,the hue of the numeric value 206 shown may be yellow in accordance withoperation S132 to indicate that the vehicle 10 is in the advisory statewith respect to a particular tire 40, and the hue of the numeric value206 shown may be green, for example, or a standard secondary hue for thedisplays 20 and 32 in accordance with operations S144 to indicate thatthe vehicle 10 is in the optimum state with respect to a particular tire40.

Alternatively or additionally to changing the hue of the numeric value206 shown to indicate whether the vehicle 10 is in the warning state,the advisory state or the optimum state with respect to a particulartire 40, in a similar manner, the hue of the symbol 208 shown in theforeground of the background display 204 may be changed in accordancewith the respective operations S106 and S132 to indicate whether thevehicle 10 is in the warning state or the advisory state with respect toa particular tire 40.

As shown in FIG. 12, if the vehicle 10 is identified as being in thewarning state with respect to a particular tire 40, the correspondingsector 202 can additionally show a telltale 210 in the foreground of thebackground display 204 to output a warning of low tire inflationpressure in accordance with operation S106 a. As shown, the telltale 210can be similar in appearance to the malfunction indicator light 24.According to this example, it is contemplated that the telltale 210 canbe shown in satisfaction of TPMS requirements in lieu of actuating themalfunction indicator light 24. Alternatively, it will be understoodthat the telltale 210 can be shown in addition to actuating themalfunction indicator light 24 if the vehicle 10 is identified as beingin the warning state.

As shown in FIG. 9, it will be understood that the optimum stateindication can be output in accordance with operation S144 in partthrough the absence of showing a symbol 208 to output an instructionaccording to operations S106 c and S132 c for adjusting the inflationpressure of the tire 40 into the optimum pressure range or a telltale210 to output a warning of low tire inflation pressure in accordancewith operation S106 a.

The second field 200 b can show text 212 and text 214 to output aspectsof the warning state indication, the advisory state indication and theoptimum state indication in greater detail. The second field 200 b canshow the text 212 to output information concerning immediate action, ifany, required as a result of the vehicle 10 being identified as being inthe warning state with respect to a particular tire 40. As shown in FIG.12, for example, if immediate action is required, the text 212 can beconfigured to output an instruction according to operation S106 c foradjusting the inflation pressure of the tire 40 into the optimumpressure range so that the vehicle 10 will exhibit optimum performance.Alternatively, if the vehicle 10 is not identified as being in thewarning state, the text 212 can be configured to output an instructionthat no immediate action is required, as shown in FIGS. 9-11.

The second field 200 b can show the text 214 to output informationconcerning the action recommended when the vehicle 10 is identified asbeing in the advisory state with respect to a particular tire 40. Asshown in FIGS. 10-12, for example, the text 214 can be configured tooutput an instruction according to operation S132 c for adjusting theinflation pressure of the tire 40 into the optimum pressure range sothat the vehicle 10 will exhibit optimum performance. In addition, thetext 214 can be configured to output a description according tooperation 132 b of the one or more undesirable performancecharacteristics that the vehicle is exhibiting because the inflationpressure of the tire 40 is within the advisory pressure range.Alternatively, as shown in FIG. 9, if the vehicle 10 is not identifiedas being in the warning state or the advisory state, the text 214 can beconfigured to output a description of the one or more optimumperformance characteristics that the vehicle is exhibiting because theinflation pressure of the tire 40 is within the optimum pressure rangeaccording to operation S144 b.

The hue of the text 212 and/or the text 214 could be a standardsecondary hue for the displays 20 and 32. Alternatively, the hue of thetext 212 and/or the text 214 could be matched to the hue of thebackground display 204, the hue of the numeric value 206 and/or thesymbol 208 shown in the foreground of the background display 204according to one or more of the operations S106, S132 and S144 describedabove.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiments but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims, which scope is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures as is permitted under the law.

1. A tire pressure optimization system for a vehicle, comprising: apressure detection device for detecting a first vehicle tire's inflationpressure; a second pressure detection device for detecting a secondvehicle tire's inflation pressure; a display; and a controller incommunication with the first and second pressure detection devices andthe display, the controller programmed to: calculate a pressuredifferential between the first vehicle tire's inflation pressure and thesecond vehicle tire's inflation pressure; identify an operating state ofthe vehicle as being: in a warning state when the first inflationpressure is below a warning low pressure threshold, in an optimum statewhen the first inflation pressure is within an optimum pressure rangewhere the vehicle will exhibit optimum performance, in an advisory statewhen the first inflation pressure is within an advisory pressure rangewhere the vehicle will exhibit an undesirable performancecharacteristic, wherein the advisory pressure range is outside of theoptimum pressure range and above the warning low pressure threshold, andin the advisory state when the pressure differential is greater than anoptimum pressure differential; and operate the display to output anoptimum state indication when the operating state is in the optimumstate, a warning indication when the operating state is in the warningstate, and an advisory indication when the operating state is in theadvisory state.
 2. The system of claim 1, wherein the optimum pressurerange is defined by an optimum low pressure threshold that is higherthan the warning low pressure threshold, and an optimum high pressurethreshold.
 3. The system of claim 2, wherein the controller is furtherprogrammed to: identify the operating state of the vehicle as being in asecond warning state when the inflation pressure is above a warning highpressure threshold, wherein the advisory pressure range includes anyinflation pressure that is between the warning low pressure thresholdand the optimum low pressure threshold, and any inflation pressure thatis between the warning high pressure threshold and the optimum highpressure threshold.
 4. The system of claim 2, wherein the optimum lowpressure threshold is approximately 5 psi below a placard inflationpressure, and the optimum high pressure threshold is approximately 5 psiabove the placard inflation pressure.
 5. (canceled)
 6. The system ofclaim 1, wherein the advisory pressure range is defined as including anyinflation pressure that is: between an optimum low pressure thresholdand the warning low pressure threshold, above an optimum high pressurethreshold, or outside of the optimum pressure differential.
 7. Thesystem of claim 1, wherein the warning low pressure threshold is thehigher of a pressure 25% below a placard inflation pressure and aminimum pressure for the tire specified by the NHTSA.
 8. The system ofclaim 1, wherein the controller is further programmed to: identify theundesirable performance characteristic based on the inflation pressurewhen the vehicle is identified as being in the advisory state.
 9. Thesystem of claim 8, wherein the identified undesirable performancecharacteristic is at least one of a ride characteristic, an efficiencycharacteristic or a tire wear characteristic.
 10. A vehicle, comprising:a first tire; a pressure detection device for detecting the first tire'sinflation pressure; a second tire; a second pressure detection devicefor detecting the second vehicle tire's inflation pressure; a display;and a controller in communication with the pressure detection devicesand the display, the controller programmed to: calculate a pressuredifferential between the first tire's inflation pressure and the secondtire's inflation pressure; identify an operating state of the vehicle asbeing: in a warning state when the first inflation pressure is below awarning low pressure threshold, in an optimum state when the firstinflation pressure is within an optimum pressure range where the vehiclewill exhibit optimum performance, in an advisory state when the firstinflation pressure is within an advisory pressure range where thevehicle will exhibit an undesirable performance characteristic, whereinthe advisory pressure range is outside of the optimum pressure range andabove the warning low pressure threshold, and in the advisory state whenthe pressure differential is greater than an optimum pressuredifferential; and operate the display to output an optimum stateindication when the operating state is in the optimum state, a warningindication when the operating state is in the warning state, and anadvisory indication when the operating state is in the advisory state.11. The vehicle of claim 10, wherein the optimum pressure range isdefined by an optimum low pressure threshold that is higher than thewarning low pressure threshold, and an optimum high pressure threshold.12. The vehicle of claim 11, wherein the controller is furtherprogrammed to: identify the operating state of the vehicle as being in asecond warning state when the inflation pressure is above a warning highpressure threshold, wherein the advisory pressure range includes anyinflation pressure that is between the warning low pressure thresholdand the optimum low pressure threshold, and any inflation pressure thatis between the warning high pressure threshold and the optimum highpressure threshold.
 13. The vehicle of claim 11, wherein the optimum lowpressure threshold is approximately 5 psi below a placard inflationpressure, and the optimum high pressure threshold is approximately 5 psiabove the placard inflation pressure.
 14. (canceled)
 15. The vehicle ofclaim 10, wherein the advisory pressure range is defined as includingany inflation pressure that is: between an optimum low pressurethreshold and the warning low pressure threshold, above an optimum highpressure threshold, or outside of the optimum pressure differential. 16.The vehicle of claim 10, wherein the warning low pressure threshold isthe higher of a pressure 25% below a placard inflation pressure and aminimum pressure for the tire specified by the NHTSA.
 17. The vehicle ofclaim 10, wherein the controller is further programmed to: identify theundesirable performance characteristic based on the inflation pressurewhen the vehicle is identified as being in the advisory state.
 18. Thevehicle of claim 17, wherein the identified undesirable performancecharacteristic is at least one of a ride characteristic, an efficiencycharacteristic or a tire wear characteristic.
 19. A vehicle, comprising:a plurality of tires; a plurality of devices, each associated with oneof the plurality of tires for detecting the associated tires' inflationpressures; a display; and a controller in communication with theplurality of devices and the display, the controller programmed to:calculate a pressure differential between a first inflation pressure ofone of the plurality of tires and a second inflation pressure of anotherof the plurality of tires; identify an operating state of the vehicle asbeing: in a warning state when any of the inflation pressures are belowa warning low pressure threshold or above a warning high pressurethreshold, in an optimum state when all of the inflation pressures arewithin an optimum pressure range where the vehicle will exhibit optimumperformance, the optimum pressure range defined for each inflationpressure by an optimum low pressure threshold, an optimum high pressurethreshold, and an optimum pressure differential from another vehicletire's inflation pressure, and in an advisory state when any of theinflation pressures are within an advisory pressure range where thevehicle will exhibit an undesirable performance characteristic, theadvisory pressure range for each inflation pressure defined as includingany inflation pressure that is between the optimum low pressurethreshold and the warning low pressure threshold, between the optimumhigh pressure threshold and the warning high pressure threshold, oroutside of the optimum pressure differential from another vehicle tire'sinflation pressure; and operate the display to output an optimum stateindication when the operating state is in the optimum state, a warningindication when the operating state is in the warning state, and anadvisory indication when the operating state is in the advisory state.20. The vehicle of claim 19, wherein the controller is furtherprogrammed to identify the undesirable performance characteristic basedon the inflation pressure when the vehicle is identified as being in theadvisory state.